The phases of a clinical trial

Researchers spend many years developing new treatments or medicines in the laboratory before involving people. They then plan the clinical trial to progress in a series of up to four steps called phases. Information gathered in each phase determines whether the study can move on to the next phase, and whether the drug or treatment is approved for use. See below for a description of the different phases.

To find out how to get involved in a clinical trial or another type of study, see Joining a study.

What are Phase 0 trials?

These are exploratory studies, sometimes referred to as “microdosing” or “pilot studies”. These trials are less common, and are used to test how the body responds to an experimental drug and whether it is worth moving on to a Phase 1 trial. A small dose of the drug is given once or for a short time to 10–15 people, sometimes to healthy volunteers. These trials do not offer any direct benefit to participants.

How the different phases work

Phase 1

Participants

10–100

Purpose

first study in people

tests safety of new treatment

finds the safest dose and the best way a treatment can be given

identifies side effects

studies how the intervention works with other medicines or food (interactions)

How it works

participants are given a fixed dose and watched closely for side effects

if no side effects, dose is increased in next group of participants, this continues until noticeable side effects appear

More info

patients sometimes benefit from having the new treatment but great improvements in their condition are uncommon

Phase 2

Participants

100–300

Purpose

builds on the results of Phase 1

continues to test safety of a drug

begins to assess how well a new treatment works on the disease

How it works

often focuses on one cancer type

all participants receive the same experimental treatment

sometimes randomised controlled trial – i.e. participants are put into separate groups and given different treatments, which are then compared to see how well they treat the disease

More info

people often have treatment as an outpatient, but occasionally need to stay overnight in hospital for monitoring

Phase 3

Participants

100s–1000s

Purpose

tests if the new treatment is better than the standard treatment

compares side effects, survival and quality of life

assesses whether the risks outweigh the benefits

collects information that allows new treatments and existing treatments to be used in new ways or for different diseases

Amazon Kindle 2nd Generation devices

EPUB files can’t be read on the Amazon Kindle™. However, like most eReaders, Kindle™ 2nd Generation devices are able to display PDFs. We recommend that you download the PDF version of this booklet if you would like to read it on a Kindle™.
To transfer a PDF to your Kindle™ via USB cable from your computer or Mac:

download the PDF directly onto your computer.

connect the USB cable to your computer’s USB port, and the micro USB end of the cable to your Kindle™. Note: the Kindle™ won’t be available as a reading device while it is connected to your computer until it has been disconnected.

open the Kindle™ drive and several folders will appear inside. The “Documents” folder is where you will need to copy or drag the PDF to.

safely eject your Kindle™ from your computer and unplug the USB cable. Your content will appear on the Home Screen.

Android and PC

You can also download and open eBooks on Android devices and PCs with appropriate apps or software installed. Suitable eReader apps for Android include Google Play Books, FBReader and Moon+ Reader. Suitable software for PCs include Calibre and Adobe Digital Editions.

The cancer information on this website is based on the Understanding Cancer series booklets published by Cancer Council. This information is reviewed and updated every three years or as new information comes to hand. Cancer Council works with cancer doctors, specialist nurses or other relevant health professionals to ensure the medical information is reliable and up to date. Consumers also check the booklets to ensure they meet the needs of people with cancer. Before commencing any health treatment, always consult your doctor. This information is intended as a general introduction and should not be seen as a substitute for your own doctor’s or health professional’s advice. All care is taken to ensure that the information contained is accurate at the time of publication.

Support services

Coping with cancer?Speak to a health professional or to someone who has been there, or find a support group or forum

Amazon Kindle 2nd Generation devices

EPUB files can’t be read on the Amazon Kindle™. However, like most eReaders, Kindle™ 2nd Generation devices are able to display PDFs. We recommend that you download the PDF version of this booklet if you would like to read it on a Kindle™.
To transfer a PDF to your Kindle™ via USB cable from your computer or Mac:

download the PDF directly onto your computer.

connect the USB cable to your computer’s USB port, and the micro USB end of the cable to your Kindle™. Note: the Kindle™ won’t be available as a reading device while it is connected to your computer until it has been disconnected.

open the Kindle™ drive and several folders will appear inside. The “Documents” folder is where you will need to copy or drag the PDF to.

safely eject your Kindle™ from your computer and unplug the USB cable. Your content will appear on the Home Screen.

Android and PC

You can also download and open eBooks on Android devices and PCs with appropriate apps or software installed. Suitable eReader apps for Android include Google Play Books, FBReader and Moon+ Reader. Suitable software for PCs include Calibre and Adobe Digital Editions.

Cancer Council NSW would like to acknowledge the traditional custodians of the land on which we live and work.We would also like to pay respect to the elders past and present and extend that respect to all other Aboriginal people.

Cancer Council NSW would like to acknowledge the traditional custodians of the land on which we live and work.We would also like to pay respect to the elders past and present and extend that respect to all other Aboriginal people.

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